Benchmark try/except vs. conditionals for caching (short-lived objects)

try_except_vs_cond2.py

#!/usr/bin/env python

import timeit


class Foo:
    base_url = "http://boo"

    def __str__(self):
        try:
            return self._str
        except AttributeError:
            clsname = type(self).__name__
            self._str = f"{clsname}({self.base_url!r})"
            return self._str


class Bar:
    base_url = "http://boo"

    def __str__(self):
        if hasattr(self, "_str"):
            return self._str

        clsname = type(self).__name__
        self._str = f"{clsname}({self.base_url!r})"
        return self._str


class Baz:
    base_url = "http://boo"

    def __str__(self):
        if not hasattr(self, "_str"):
            clsname = type(self).__name__
            self._str = f"{clsname}({self.base_url!r})"
        return self._str


print(
    "foo:",
    timeit.Timer(stmt="foo = Foo(); str(foo)", globals=locals()).timeit(),
)
print(
    "bar:",
    timeit.Timer(stmt="bar = Bar(); str(bar)", globals=locals()).timeit(),
)
print(
    "baz:",
    timeit.Timer(stmt="baz = Baz(); str(baz)", globals=locals()).timeit(),
)